期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1974
卷号：71
期号：7
页码：2872-2876
DOI：10.1073/pnas.71.7.2872
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The activity of the {sigma} subunit of Bacillus subtilis RNA polymerase decreases markedly during the first hours of sporulation [T.G. Linn et al. (1973) Proc. Nat. Acad. Sci. USA 70, 1865-1869]. We have prepared antibody against RNA polymerase holoenzyme to determine the fate of {sigma} polypeptide during spore formation. This antiserum specifically and independently precipitates {sigma} and core polymerase from crude extracts of B. subtilis as judged by both sodium dodecyl sulfate and urea gel electrophoresis of the precipitates. We report that crude extracts of sporulating cells lacking {sigma} activity contain as much {sigma} polypeptide as extracts of vegetative cells. However, {sigma} polypeptide in extracts from sporulating cells is apparently only weakly associated with RNA polymerase, as indicated by the failure of {sigma} to co-purify efficiently with core enzyme during phase partitioning. The loss of {sigma} activity and the weak binding of {sigma} to core enzyme occurs normally in a mutant blocked at an intermediate stage of sporulation (SpoII-4Z) and in wild-type bacteria sporulating in 121B medium, Difco sporulation medium, or Sterlini-Mandelstam resuspension medium. In contrast, {sigma} in two mutants (SpoOa-5NA and SpoOb-6Z) blocked at an early stage of spore formation remains active and tightly associated with RNA polymerase during stationary phase.
